Cristiano Larghi

The transitional faunas of the Permian Huqf succession of Oman make it one of the key-sections for the intercalibration of Early to Middle Permian biostratigraphical scales. The abundance of fossils improved the knowledge of some marine faunas which populated the North-Eastern Gondwanan fringe during times of climatic changes in the Permian. A Sterlitamakian (upper Sakmarian, Lower Permian) bivalve fauna from the Saiwan Formation in the Huqf area, informally named "Dickinsartella Fauna", is described in the present paper. The specimens examined were collected from the "Pachycyrtella Bed" (Auctorum), the basal bed of the Formation in its type locality. The Dickinsartella Fauna can be identified for the presence of the new genus Dickinsartella, which dominates the bivalve thanatocoenosis with D. pistacina sp. n. (type species). The bivalve fauna from the Pachycyrtella Bed includes the new species Stutchburia sangallii and Promytilus mazzolenii, and also Astartella obliqua Dickins, 1963, Nuculopsis cf. bangarraensis Dickins, 1963, ?Oriocrassatella sp., and indeterminable aviculopectinids.This fauna shows a low taxonomic diversity. Nevertheless, some species are represented by a high number of generally well-preserved specimens, i.e. some specimens of S. sangallii sp. n. and A. obliqua show part of the ligament. The good preservation of the shells permitted the microstructural analysis of D. pistacina sp. n. and S. sangallii sp. n. The microstructure of S. sangallii sp. n. supports the close phylogenetical link between modiomorphids and crassatelloids recognized by some previous authors.The new genus Dickinsartella includes the more recent species belonging to the important Paleozoic Order Cyrtodontida Scarlato & Starobogatov, 1971.The discovery of Dickinsartella gen. n. and other taxa of the Pachycyrtella Bed, present also in the Sakmarian levels of the Carnarvon and Perth Basins in Western Australia, indicates a wider distribution of the Dickinsartella Fauna and confirms the correlation between Arabian and Australian series already remarked by previous authors.The "Dickinsartella fauna" is the first bivalve fauna testifying to the climatic amelioration gradually affecting the North-Eastern Gondwanan fringe at the end of the Early Permian glacial events. This pioneer fauna spread out, probably in a cool-temperate climate, on the substrate provided by the mid-Sakmarian (basal Sterlitamakian) transgression, connected with the final stages of the Gondwanan deglaciation and/or with initial sea-floor spreading in the Neotethys. In the present paper some remarks on the autecology of the new species from the "Pachycyrtella bed" are also discussed.

A new specimen of the protorosaurian diapsid reptile Tanystropheus is described. The specimen was collected at the Valle Serrata locality (Switzerland) and is of Ladinian (Middle Triassic) age. Its study elucidates some issues regarding the anatomy of Tanystropheus to be addressed, and allow to suggest hypotheses about its mode of life. In particular, the specimen is the first one in which the skin and other soft tissues can be described. In particular, wide patches of black phosphatic material, filled with small carbonate spherules are preserved, as it occurs in corpses lying in stagnant water due to decomposition of consistent amount of proteins. This suggests that a huge mass of flesh was present in the caudal part of the body, shifting posteriorly the center of mass of the animal and helping in balancing the weight of the neck even if raised off horizontal plane and out of water. In addition, no evidence of caudal autotomy is present in Tanystropheus and the structure of the tail and of the limbs are consistent with a shoreline habitat rather than with a fully aquatic mode of life.

JUSTIN A. SPIELMANN, ANDREW B. HECKERT, & SPENCER G. LUCAS

Two species of the unusual archosauromorph Trilophosaurus, T. buettneri Case and T. jacobsi Murry, are known from diverse localities in the Upper Triassic Chinle Group in the southwestern USA. Both species likely occupied similar ecological niches, based on morphological similarities in the postcrania, which are essentially identical. Trilophosaurus occurrences in the Chinle Group are relatively rare, but individual sites are exceptionally rich, suggesting that Trilophosaurus lived in a different paleoenvironment than more typical Chinle vertebrates, which lived in or near streams (phytosaurs, metoposaurs) or on floodplains (aetosaurs, rauisuchians, and dinosaurs). Two potential interpretations are that Trilophosaurus was either an arboreal climber or a fossorial digger. However, the gross skeletal features of Trilophosaurus are not compatible with a fossorial mode of life: the limbs are too long and gracile, proximal limb elements are longer than distal ones, and the claws are laterally compressed, not transversely broadened. The intermittent study of Trilophosaurus has caused the theory of it being arboreal, originally proposed by Gregory, to receive little mention in subsequent studies. We reexamined the functional morphology of Trilophosaurus using a qualitative functional morphological analysis of the skeleton, a quantitative examination of claw curvature, and a quantitative examination of manus/trunk and pes/trunk ratios. Claw morphology of Trilophosaurus shows similarities to the arboreal drepanosaurs Drepanosaurus and Megalancosaurus. Our analysis provides ample evidence to suggest that Trilophosaurus was arboreal.

Miloš Siblík, with contribution by Gerhard Bryda.

Upper Triassic brachiopods from 2 localities in the reef Dachstein Limestone of the SE Hochschwab massif in Styria, Austria are systematically described and illustrated. About 900 variably preserved specimens belong to 28 species, representing thus the most diverse brachiopod fauna known from the North Alpine Dachstein Limestone. This indicates that brachiopods were common inhabitants of reef habitats during the Alpine Norian. Oxycolpella, Sinucosta and Aulacothyropsis are dominant. Seven brachiopod species are known from the Kössen Formation (Rhaetian). Adygella biplicata (Dagys) and Ladinian Hungarispira loretzi (Bittner) are the newcomers in the Nordalpine Dachstein Limestone. In addition to brachiopods, only some fragments of bivalves were found. Conodonts of the species Epigondolella triangularis (Budurov 1972) indicate the Early Norian age.

MAURIZIO CHIOCCHINI, MILVIO FAZZUOLI & VIVIANA REALE

The Lower Kambe Formation crops out from Mombasa towards the northeast, along the coastal area of Kenya; it was deposited during the first phases of the Middle Jurassic marine transgression. The lithology of the Lower Kambe Fm. varies passing from the southern areas towards the north: near Mombasa, this formation consists of an alternance of calcareous and marly intervals; the marly levels become thinner and tend to disappear towards the north, where the succession becomes entirely calcareous and shows features of a carbonate platform. According to field observations, in the Mwachi River area near Mombasa, four lithological units crop out, that we consider as informal members, namely from bottom : (a) Calcarenitic member (Cam), well bedded calcarenites and some conglomerates; (b) Lower Shaly member (LSm), marly shales with marly limestone beds; (c) Conglomeratic member (Cgm), alternance of calcarenitic beds and levels of conglomerates; (d) Upper Shaly member (USm), marly shales and siltstones with thin beds of calcilutites and quartz sandstones. The sedimentological features of the Cam point to a shoreline environment, possibly shoreface; those of the LSm to a mid/outer ramp; the onset of tectonically active slopes is evidenced by the occurrence of gravity flow structures in the fine-grained sediments. At the top of LSm a marked shallowing of the deposition environment occurred. The Cgm was deposited on a inner ramp, where polymictic coarse deposits (arenaceous, shaly and carbonate clasts) indicating a strong erosion of the coastal areas, were intercalated to the wave-winnowed calcarenites; also the calcarenitic upper portion of the Cgm was deposited on an high energy inner ramp depositional environment. Upwards, a deepening occurred, as the fine sediments of the USm point to a mid/outer ramp. The age of the Lower Kambe Formation has been determined by several Authors on the basis of ammonites; in this work calcareous nannofossils stratigraphy is provided. The age given by ammonites is Bajocian; the calcareous nannofossil assemblage, found in various localities along the Mwachi River, indicates an Aalenian - Bajocian p.p. age. The discrepancy is possibly due to a complex geological situation (faults ?) in the localities with ammonites.

Luca GIUSBERTI, Marco FANTIN & John BUCKERIDGE

A new species of irregular echinoid, Ovulaster protodecimae, is described from the Danian Scaglia Rossa Formation outcropping in the Venetian Prealps (Southern Alps, northeastern Italy). The new species, belonging to the order Spatangoida, is very distinctive because of its inflated, almost triangular test, the high-positioned periproct and the plate arrangement on the oral face. This is the first report of the genus Ovulaster in the Danian of Italy and the first description of an echinoid from the Early Palaeocene of Italy. One test has an epifauna of the sessile verrucid barnacle Verruca sp. cf. V. prisca Bosquet, 1854, attached on all except the oral surface.

MASSIMILIANO GHINASSI, LAURA ABBAZZI, DANIELA ESU, JEAN GAUDANT & ODOARDO GIROTTI

The Upper Valdarno Basin, one of the most investigated Neogene–Quaternary basins of the Northern Apennines, developed during three main phases, as testified by the occurrence of three unconformity-bounded stratigraphic units (UBSUs) in the basin infill. Despite numerous studies having been carried out, biochronological, paleoecological and stratigraphical issues in the lower portion of the Montevarchi Synthem (second phase) have yet to be understood. Sandy deposits (Montecarlo Sand and Silt Unit), stratigraphically located in this portion of the Montevarchi Synthem, are the focus of this multidisciplinary study. These deposits conformably overlie sandy fluvio-eolian sediments and are, in turn, capped by fluvio-palustrine deposits through a progressive unconformity. Facies analysis suggest a sandy flood-basin environment for these deposits, characterised by variations in water discharge and flood event energy. Mollusc and fish remains, pointing to quiet or slow-moving shallow waters, have been affected by transport processes before final burial in overbank areas. Fish remains of the primary marine family Mugilids highlight a connection between the basin and the sea that was previously only supposed. Small mammal remains, referred to the rodent Mimomys polonicus, are coherent with a water-rich environment. Cyclic variations in shell content and sedimentological characteristics testify to the occurrence of short-term climatic oscillations during this warming phase. This study fits with paleomagnetic and radiometric datings and mammal biochronology, in indicating that the Montecarlo Sand and Silt Unit belongs to a time interval preceding the Reunion paleomagnetic event. The depositional evolution of the Montecarlo Unit was driven by climatic change from arid to humid conditions, related to a global increase in temperature that occurred between 2.4 and 2.2 Ma.

Lorenzo Rook & Raffaele Sardella

We describe fossil remains attributable to genus Hystrix, collected from fissure filings in the area between Apricena and Poggio Imperiale (Apulia, Italy). The vertebrate assemblage that yielded these Hystrix remains is known in the literature as Pirro Nord, and is one of the richest Early Pleistocene mammal assemblages from Italy. The porcupine remains from Pirro Nord are attributed to the species Hystrix refossa. The problem of the taxonomy of Plio-Pleistocene hystricids in the framework of their morphological variability is discussed.

LAURA ABBAZZI, MARISA ARCA, CATERINELLA TUVERI & LORENZO ROOK

This paper presents the main results related to the analysis of fossils of the endemic Sardinian canid Cynotherium, discovered during the past years within the rich fossiliferous karst deposits in the Monte Tuttavista area (Eastern Sardinia, Nuoro). The analysis indicates that the remains from various fissure infillings differ in size and dental characters, which are suggestive of evolutionary phases under endemic conditions. The chronological sequencing of fissures obtained based on the evolutionary stage of the fossil canid is consistent with that emerging from the analysis of the whole mammal assemblages occurring in the same fissures. The possible evolutionary relationships of the Sardinian canid to the Plio-Pleistocene mainland species are also considered; a derivation from a population of late Canis arnensis (or Canis mosbachensis) population is supported.